Electromagnetic contactor



y 1939- w. c STEVENS 2,158,841

ELECTROMAGNETIC CONTACTOR Filed Aug. 28; 19:57

Patented May 16, 1939 2,158,841

UNITED STATES PATENT OFFICE ELECTROMAGNETIC CON TACTOR William 0. Stevens, Milwaukee, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application August 28, 1937, Serial No. 161,364

.10 Claims. (01.175-338) An object of the invention is to generally imployed. 5 prove and simplify the details of construction Fig. '7 is a fragmentary sectional view similar to and assembly of the parts of electromagnetic Fig. 2, but showing a modification wherein the contactors. armature stop element is formed integrally with Another object is to provide a novel form of the combined shading coil andcoil clamp memcombined shading coil and coil clamp for alterher, and v 10 nating current contactors. Fig. 8 is a detail perspective view of the com- Another object is to provide for ready removal bined shading coil, coil clamp and armature stop of the combined shading coil and coil clamp, member illustrated in Fig. 7.

to facilitate replacement thereof and to permit Referring first to Figs. 1 to 5, inclusive, the

5 inspection of other parts of the contactor. numeral l0 designates a base or plate formed of 5 Another object is to provide a novel form of suitable insulating material, such as a laminated stop for the armature of the contactor. fiber board impregnated with the phenol formal- Another object is to provide novel means for dehyde condensation product sold commercially adjustably mounting-the armature stop. under the trade name of Bakelite. Plate I0 Another object is to provide a one-piece commay be provided with two or more suitably posi- 20 'bined shading coil, coil clamp and armature tioned openings (not shown) to facilitate attachstop, together with novel means for removably ment thereof to a panel or the like.

- mounting the same. Secured to plate ID as by means of a pair of Another object is to provide novel means for screws H is a magnet core member l2 of subresiliently and frictionally mounting the operstantially U-shape,-said member having a relaating winding with respect to the magnet core. tively short arm l3 and a relatively long arm I4. Another object is to provide a novel form of Arm I 4 is beveled, as shown in Fig. 2, to provide a bridging contactor and novel means for releasknife-edge l5. Member I2 is preferably composed ably supporting the same in assembled relation of a metal strip bent to the form illustrated.

1:0 to the armature. Loosely pivoted upon the relatively long arm Other objects and advantages of the invention M and adapted to bear against the knife edge will hereinafter appear. 15 is an armature l6, which is preferably'cut to The accompanying drawing illustrates certain the desired length from a metal strip. To assist embodiments of the invention which will now be in pivoting armature 16 to arm I4 I preferably .2.) described, it being understood that the embodi spot weld or otherwise rigidly attach to the ments illustrated are susceptible of modification former a bracket I! having a portion l8 which in respect of certain details of construction thereoverlies a portion of the inner Surface 0f arm of without departing from the scope of the apand a pair of downwardly extending lugs l9 and pended claims. a 20 which respectively engage opposite edges of 10 In the drawing, said arm. 40

Figure 1 is a plan View f an alternating cur... Armature I6 is provided adjacent its lower rent contactor constructed in accordance with end with drilled recess cavity which is my invention I adapztgd fto receivie tthe specially fgme arc lhhoiilrcled 3 g t n inv we end 0 a coie ension spring e 0 er 1:, "1'stant1a11y on the 214m fof sprinfg 23 is 1p rcg'i deddwitthdathookedtexiadousua orm,w1c isaape openerae g i i lg iz fifiggg :22 :2 i 2 2 :3 an opening 25 and notch 2B in portion 21 of a to Show the arrangement of the combined Sh bracket 28 wh1ch is spot welded or otherwise rigidly secured to the lower surface of arm I4, as

mg 0011 and clamp for the operating coil or windshown in Figs. 2 and 3' spring 23 thus acts to 50 mg 9 contaciorbias armature IE to its retracted position,suit- 4 1s a detall Perspectlve Vlew of the able means being provided to limit the degree of bmed Shading and coil clamp memberretracting movement of the armature, as herein- Fig. 5 is a detail perspective view of one of the after described.

reflexed resilient members to be frictionally inter- 55 This invention relates to improvements in electromagnetic contactors. Certain features of the invention are particularly applicable to alternating current contactors.

posed between the laminated core arm and the operating winding associated with the latter.

Fig. 6 is a detail perspective view of the adjustable armature stop member which may be em- Armature I6 is provided with a drilled opening to receive the reduced shank 29 of a pin 34, and a countersink or recess to accommodate the upset end of said shank, as shown at 30, in a relation flush with or within the inner surface of said armature. Armature it is provided with a second drilled opening, alined with the opening aforementioned, to accommodate the shank of a rivet 32. Telescoped onto rivet 32 between the head 33 of the latter and the outer surface of armature 46 are a pair of metal washers 34 and 35 and a tube or ferrule 36,a coiled compression spring 3?! bearing at one end against washer 34 and surrounding washer 35 to be centered by the latter.

Carried by armature I6 is a bridging contactor 38 of substantially T-shape,the head of said contactor having an open slot 39 which accommodates witha sliding fit the aforementioned ferrule 36 surrounding rivet 32. That portion of slot 39 which surrounds ferrule 36 is provided with an upstanding flange 44 (Fig. 2) which is accommodated by the inner end of spring 37, whereby contactor 38 is yieldably biasedtoward, or into a given relationship to, the armature it. The shank portion of contactor 38 is provided with a circular opening 4! 'to loosely accommodate the aforementioned rivet 3ll,--an upstanding fiange 42 surrounding said opening for cooperation with said rivet to assist in retaining said contactor in proper relationship to armature I6. As shown in Fig. 2 the shank of rivet 32 is upset, as indicated at 43, whereby the same is mounted in a rigid position with respect to armature l6.

Rigidly secured to core member l2 between arms l3 and i4 is a laminated core arm 44, the laminations of which are rigidly attached or clamped to each other, as by means of a rivet 45. The means for securing arm 44 to core I2 preferably comprises a pair of flat-head screws (not shown) countersunk into the outer surface of member l2, and taking into correspondingly located tapped openings provided in the inner end of arm 44. The outer end of arm 44 is-preferably located in or ground to a plane flush with the outer end of long arm l4,--and said end of arm 44 is provided with a kerf or groove 46 to accommodate the shading coil hereinafter described. I preferably interpose between the inner end of arm 44 and core member 62 an insulating plate or spacer 4'l.

Adapted to surround arm 44 is a preformed operating winding or coil 4t,-the wiring terminals of which extend from opposite sides thereof as shown at 49 and 54 in Figs. 1 and 3. Winding 48 is frictionally but removably retained in proper position with respect to arm 44 as by means of a pair of reflexed resilient metal members 5i arranged on opposite sides of arm 44.

(Fig. 3), one of said members being shown in detail in Fig. 5. Members 50 are positioned with the bent portions thereof adjacent the outer end of arm 44, and winding 48 is then pressed inwardly to the position thereof shown in Fig. 2.

Superimposed upon the upper surface of short arm 43 (Fig. 2) is the horizontal portion 52 of a combined shading coil for the outer face -of arm 44 and clamp for winding 45. Said combined member is preferably of inverted L-shape, and the vertical portion thereof is adapted to overlap the outer end of arm l l,said vertical portion having an opening 54 to accommodate a portion of the pole face of arm 44.-the part 55 of said vertical portion being adapted to fit within the aforementioned groove 46, whereby a shading coil is provided for the pole face of said arm 44. As shown, the vertical portion 53 overlaps a portion of winding 48, whereby endwise displacement of the latter from arm 44 is positively prevented.

Superimposed upon horizontal portion 52 is a stop 56 for the armature l6. Stop 56 preferably comprises a fiat punched metal plate having a rectangular opening 5i (Fig. 2) which is adapted to accommodate the reduced upper end or extension 58 of armature l 6. The outer wall 59 of opening 57 is adapted for engagement by the outer surface of extension 58 of armature E5 to limit the degree of retracting movement of the latter. If it is desired to increase the air gap between armature l6 and the pole face of arm 44 this may be accomplished by filing or grinding away to the desired extent the wall 59 of opening 5'l.

As shown, the short arm l3 (Fig. 2) of core member i2 is provided with a pair of tapped openings to receive the shanks of a pair of screws till,horizontal portion 52 and stop plate 56 having openings to provide clearance for said screw shanks. Interposed between the heads of said screws and plate 56 are suitable lock washers 6| to prevent accidental loosening thereof. By this arrangement horizontal portion 52 and plate 56 may be rigidly secured to core arm l3. By reason of the clearance between the walls of the openings in plate 56 and the shanks of screws 60 a slight degree of adjustment of the position of wall 59 of opening 5'! in said plate may be effected prior to tightening of said'screws.

As shown in the modified form of armature stop plate 56 of Fig. 6, a greater degree of adjustment of the position of wall 59 of opening 51" may be effected by providing elongated or elliptical clearance openings for the shanks of securing screws 60, as indicated at 62 and 83. Such an arrangement obviates the necessity for filing or grinding away the wall 59 of the plate opening to provide the desired air gap between armature l6 and the pole face of arm 44. The

arrangement illustrated in Fig. 6 likewise provides l for an adjustment to decrease the amount of the air gap when desired. It will beunderstood, of course, that plate 56 may be substituted for the plate 56 of Figs. 1 and 2 without requiring any changes in the other elements of the contactor.

As bestillustrated in Fig. 1, contactor 38 has attached to the inner surface of the opposite ends thereof a pair of contact tips, shown in dotted lines at 64 and 65. substantially cylindrical form,the contacting portions preferably being composed of coin silver with a backing or layer of nickel silver alloy, whereby the same may be rigidly attached to contactor 34 by a welding operation.

The stationary contacts likewise preferably comprise plates iii and El to which tips 68 and 659 of the aforementioned character are rigidly attached, as by welding. Plates 66 and till are rigidly secured by screws "ill and "H to the angularly arranged forward end portions of a pair or" brackets 72 and -'J'3,.said brackets being of approximately .U -shape, as best illustrated in Fig. 2. The rear end portions and ill of brackets l2 and is are attached to insulating plate id as by means of pairs of screws, the pair of attaching screws "l5 and ill for portion being shown in 2, and one screw of the pair associated with portion l5 being shown in Said tips are preferably of I.

Figs. land 3. The shanks of screws H and W are made relatively long, whereby each is adapted to receive a clamping nut I8 (Fig. 2), a cup washer 88, a wire clamping nut 8|, and a slotted nut 82 which may act as a lock for nut 8|.

In Figs. '7 and 8 I have shown a modified form of the device wherein a single metal member 83 is provided with a vertical portion 84 adapted to clamp or retain the operating winding 48 (Fig. 7) in assembled relation to the laminated core arm 44, arm 84 having an opening 85 formed therein to provide a shading coil for the grooved pole face of core arm 44; an integral part 88 being sheared and bent outwardly therefrom to lie substantially in the plane of the horizontal portion 81. Part 86 has an opening 88 formed therein to receive and to limit retractive movement of armature 16. As shown in Fig .7, the screws 8| for attaching horizontal portion 81 of member 83 to the relatively short core arm ii are slightly shorter than the screws SI of Fig. 2. The other elements of the device of Fig. 7 are like the corresponding parts aforedescribed and have been given like numerals of reference.

In practice I prefer to form the bridging contactor 38 of phosphor bronze. The combined shading coil and coil clamp member 53 and the armature stop plates 56 and 58-, in figs. 1 to.5, are preferably formed of a suitable non-magnetic material, such as brass. Similarly. the onepiece combined shading coil, coil lamp and armature stop member 88 of Figs. 7 and 8 is preferably formed of brass. The magnetic core and armature elements of the contactor are, of course, preferably formed of steel.

What I claim as new and desire to.secure"by Letters Patent is:

1. In an electromagnetic contactor, in combination, a magnet core comprising three parallel arms, an operating winding surrounding the intermediate arm and spaced inwardly from the free end of the latter. a one-piece substantially L-shaped sheet metal member having one portion attached to an outer arm of said core arid an integral loop-shaped portion overlapping the free end of said core arm first mentioned. said free end having a groove formed inthe forwardface thereof and said loop-shaped portion having an integral part formed to fit within said groove whereby a shading coil is provided, and said loopshaped portion also acting to positively prevent displacement of said operating winding from said magnet core.

2. In combination, a magnet core of substantially E-form, a magnetizing coil surrounding the intermediate arm of said core, said intermediate arm being of laminated form and having a groove formed in the pole-face thereof, a one-piece metal strip bent to substantially L-shape, one arm of said strip being secured to an end arm of said core and the other arm of said strip being arranged in overlapping relation to the pole face of said intermediate arm of the core, said overlapping arm of the strip having an opening formed therein to accommodate a portion of said pole face, an integral portion of said last mentioned arm being adapted to fit within the groove in said pole-face whereby a shading coil is provided for the latter, said last mentioned am also acting to positively prevent displacement of said shading coil and coil clampmember, said member comprising a sheet metal strip bent to substantially L-shape, the horizontal portion of said member having a plurality of openings formed therein, a plurality of fastening elements penetrating said openings and engaged with another of'said core arms to rigidly secure said parts in assembled relation, said first mentioned core arm having a groove formed in the pole face thereof, the vertical portion of said member having an. opening formed therein adjacent to the freeend thereof, said last mentioned opening being surrounded by the metal of said strip and the same being adapted to accommodate a portion of the grooved pole face aforementioned, whereby a shading coil is provided, and said vertical portion also acting to retain said magnetizing coil in position upon said core arm first mentioned.

4. As an article of manufacture, a combined shading coil, coil clamp and armature stop member for alternating current magnets, said member comprising a metal strip bent to provide a horizontal portion and a vertical portion, said horizontal portion being formed to provide for rigid attachment thereof to one arm of a magnet core, said vertical portion having an opening formed therein adjacent thelower end thereof to accommodate a portion of the grooved pole face of another arm of the magnet core, whereby a shading coil is provided, said vertical portion also acting to clamp a suitable magnetizing winding in assembled relation to said last mentioned arm of the core, said vertical portion having an integral portion of substantially loop-shape sheared and bent with respect thereto to lie substantially within the plane of said horizontal portion, and said portion of loop-shape being adapted to accommodate therewithin a portion of an armature, to thereby positively limit movement of the armature in one direction.

5. In combination, a combined shading coil and coil clamp member for alternating current magnets, said member comprising a metal strip bent to provide a horizontal portion and a vertical portion, said horizontal portion being formed to provide for rigid attachment thereof to one arm of a magnet core, said vertical portion having an opening formed therein adjacent the lower end thereof and surrounded by the metal of said strip to accommodate a portion of the grooved pole face of another arm'of the magnet core, whereby a shading coilis-provided, said vertical portion also acting to clamp a suitable magnetizing winding in assembled relation to said last mentioned arm of the core, and an element arranged in fixed relation to said combined member aforementioned, said element having an opening formed therein, one wall of said opening being engageable by an armature of suitable form to positively limit movement of the latter when released. I

6. In combination, a combined shading coil and coil clamp member for alternating current magnets, said member comprising a metal strip bent to provide a horizontal portion and a vertical portion, said horizontal portion being adapted to be superimposed upon one arm of a magnet core of suitable form, an armature stop comprising a fiat member superimposed upon said horizontal portion, a pair of securing screws, said flat member and said horizontal portion having openings to provide clearance for the shanks of said screws, which take into tapped openings provided in said core arm whereby said flat member and said horizontal portion may be clamped in' position, the aforementioned openingsin. said flat member being of elongated form to provide for a substantial degree of adjustment of said fiat member relatively to said core arm, said fiat member having a relatively large opening formed in the free end thereof to accommodate a portion of the magnet armature, the outer wall of said last mentioned opening being adapted to positively limit the degree of releasing movement of the armature, the aforementioned vertical portion of said combined element having an opening formed therein adjacent the lower end thereof and surrounded by the metal of said strip to accommodate a portion of the grooved pole face of another arm of the magnet core, whereby a shading coil is provided, and said vertical portion also acting to clamp a suitable magnetizing winding in assembled relation to said last mentioned arm of the core.

7. in an alternating current contactor, in combination, a magnet core comprising a metal strip bent to approximately lJ-shape to provide a relatively long arm and a relatively short arm, an armature pivotally supported by said relatively long arm, said core having attached thereto an intermediate arm of a length corresponding to said relatively long arm, said intermediate arm being of laminated construction and having a groove formed in the forward face thereof, an operating winding surrounding said intermediate arm, a non-magnetic member of inverted shape having a portion attached to said relatively short arm and another portion adapted to overlap said forward face of the intermediate arm, said last mentioned portion having an opening formed therein to accommodate a portion of said forward face, an integral part of the surrounding wall of said opening being adapted to fit within said groove to provide a shading coil for said forward face, and said last mentioned portion being adapted to overlap a portion of said operating winding, whereby the latter is positively restrained against displacement from said intermediate arm.

8. In an alternating current contactor, in com bination, a magnet core comprising a metal strip bent to approximately U-shape to provide a relatively long arm and a relatively short arm, an armature pivotally supported by said relatively long arm, said core having attached thereto an intermediate arm of a length corresponding to said relatively long arm, said intermediate arm being of laminated construction and having a groove formed in the forward face thereof, an operating winding surrounding said intermediate arm, a plurality of reflexed resilient metal members interposed between said intermediate arm and the adjacent inner surfaces of said winding, whereby the latter is frictionally held in position, a member of inverted L shape having a portion attached to said relatively short arm and another portion adapted to overlap said forward grease-i face of the intermediate arm, said last mentioned portion having an opening formed therein to accommodate a portion of said forward face, an integral part of the surrounding wall of said opening being adapted to fit within said groove to provide a shading coil for said forward face, and said last mentioned portion being adapted to overlap a portion of said operating winding, whereby the latter is positively restrained against displacement from said intermediate arm.

9. In an alternating current contactor, in combination, a magnet core having a laminated arm of substantially rectangular form in cross section, a pair of refiexed resilient metal strip members of substantially V-shape respectively positioned on opposite sides of said arm, the bent portions of said members being positioned adjacent the forward end of said arm, an operating winding telescoped onto said arm and engaged with the outer arms of said members to be frictionally retained in position by the latter, and a one-piece punched and stamped sheet metal shading coil member removably secured to another arm of said core and having an integral loop-shaped portion overlapping a portion of the forward end of said laminated arm said loopshaped portion also overlapping the forward end of said winding, whereby the latter is positively restrained against displacement from said laminated arm.

10. In an alternating current contactor, in combination, a magnet core comprising a metal strip bent to substantially U-shape to provide a relatively short arm and a relatively long arm, an arm of laminated construction, rigidly secured to said core between the arms aforementioned, said laminated arm having a groove formed in the forward face thereof, an armature pivotally supported by said relatively long arm, said armature being spring biased to retracted position, an operating winding carried by said laminated arm, a one-piece inverted L-shaped sheet metal member having a horizontal portion superimposed upon said relatively short arm and a vertical portion formed for cooperation with the grooved face of said laminated arm to provide a shading coil, said vertical portion overlapping a portion of said winding to retain the latter in position, a separate sheet metal stop member having a portion superimposed upon said hori- 

